This invention relates to a mechanism for locking or fastening double-sliding doors or a dual sash window assembly in which a pair of sliding sashes are mounted in paralled and closely spaced planes within a supporting frame so as to obtain relative, horizontal sliding or rolling movements.
Many buildings are provided with double-sliding doors and a dual sash window assembly and, when the double-sliding doors or double-sliding window sashes are locked in the closed state, it has been most usual to use a crescent sash lock provided on the meeting stiles of both door sashes or window sashes. Namely, a crescent-like member pivotally mounted on the lateral face of the meeting stile of the inside sash is pivotally revolved by hand, so that the forward end of the crescent member comes into engagement with the hooked part of the receptacle plate which is mounted on the inward face of the meeting stile of the outside sash, and the inside sash and the outside sash are firmly fastened to each other.
One of the problems in the above crescent sash lock is that, although the inside and outside sashes are fastened to each other, the fastened sashes themselves are not fixedly secured in relation to the door frame or window frame and, as a result, rattling of the sashes, draught of air and leakage of rain water cannot be prevented, especially in stormy weather.
In order to solve the problem, there have been proposed several means, apart from the use of the crescent sash locks, for pushing up the sashes to the door frame or window frame so as to secure the sashes fixedly. Such push-up means of the sashes, however, has to be handled by an operation separate from the operation of the crescent sash lock and, therefore, it has become desirous to provide a locking mechanism for double-sliding doors and window sashes with which the fastening of the sashes to each other and the fixing of the thus fastened sashes to the frame can be effected simultaneously in a single operation.